Free piston engine of the opposed type



March 29, 1938. JANICKE 2,112,368

FREE PISTON ENGINE OF THE OPPOSED TYPE Filed Jan. 21, 1937 /n ve'nton:

Wx'M/ Mn J50 1118 the same characteristic. According Patented Mar. 29,1938 many,

asslgnorto'l'heresclunheraneiicnnhold. Ganiing, near Munich, GermanyApplication January 21, 1931, Serial No. 121,632

In Germany January 21, 1936 5 mm (CL 123-46) My invention relates tofree piston engines and more especially to engines of this kindbelonging to the opposed piston type, in which the opposed pistons arecoupled for synchronization by means 5 of a system of levers, pairs ofracks and gear wheels or the like.

If in engines of this type such coupling members are provided only onone side of the longitudinal axis of the engine, mass forces originatedby the masses of the coupling membersact onto the free pistons. Thesemass forces are further increased in the case where extraneous forcesoriginating from the performance of work come into play with the gearmembers, such work including, for example, the drive of a fuel pump orother auxiliary devices. These mass forces will exert tilting moments onthe pisto which are then subjected to considerable sliding pressures intheir cylinders.

My invention has for one of its objects to avoid I this drawback byproviding means whereby moments of substantially equal magnitude arecreated which however act in opposite directions and thus counteractthese tilting moments.

25 I arrange the means for creating such countermoments in thelongitudinal plane extending through the coupling members, and if theforces to be counterbalanced and the forces counterbalancing same areequally Sp from the pistons, the forces should be retardation of themasses of the to the tion of which varies greatly, stroke, from zero toa maximum zero. Obviously the moments hereby created must also bebalanced by coimteremomcnts havthereforeprovidc withtheplsacceleratothis invention I from the acceleration and retardation of oscillating orrotating masses may be balanced, as far as the momentum exerted by themon the free pistons is concerned, by counteracting forces ofcorresponding reciprocatory additional masses. 5 All these additionalmasses must also be arranged in the same longitudinal plane as themasses of. the coupling gears, however, on the opposite side of thepistons. In the drawing affixed to forming part thereof, a free pistonmotor compressor embodying my invention is illustrated diagrammaticallyby way of example in axial section.

In the drawing l is the motor cylinder, 2, 3 15 are the compressorcylinders, I, 5 are the opposed free pistons, i, I are the rackspositively coupling the two ptstons and 8 is a gear wheel mounted on themotor casing and coupling the two racks.

The rack is formedwith a cam III for the automatic operation of the fuelpump 9, a lever ll inserted between the rack 6 and the pump 9 beinglifted by the cam II, which is so arranged that the fuel pump isoperated near the end of the inward stroke of the pistons I, 5 andshortly before the direction of movement of the pistons is reversed. Theresistance force acting on the cam I! in the direction of arrow itcreates a tilting moment action on the pistons 4, 5, which tendsto turnthe pistons in the direction of the 3|) moment by which a force isacting on the cam it, counterbalancing this force. Obviously the forceacting on the cam II and the force created by the springs l5 must beinversely proportional to their distances from the middle axis of thepistons.

Special provision may be made for adapting 4c the characteristic of theadditional forces to the tim Progress of the forces to becounterbalanced. In the example here illustrated, when the roll of thefuel pump lever climbs up the cam face II, the force acting in thedirection of arrow rise at first and, after the pump piston duringthelast part of the movement of the pistons l, i. In comparison therewiththe timely progress ofthecoimteractingforce of spring I5 deviatesappreciably in that the force exerted by the springrisespermanentlinsotnearthe end ofthemovementthespringfo willenertanunbalancedtiltingmomentonthepistms. If

instanceanadditionaimass ",whichss this specification and loofitsstroke,willdropagain quickly as soon as the mass l6 hasapproximately attained the velocity at which the free pistons move. If,in the last part of the stroke, the free pistons are retardated to ahigher extent than the mass l6, no further additional force need beexerted by the free pistons and even the force required for overcomingthe rising force or the spring can be reduced, since the moving mass l6,once being set moving, will place the spring under further tension. Thusthe timely progress of the working force in the direction of arrow l2and of the additional balancing force acting on the piston 4 are keptapproximately equal. 7

Apart therefrom the mass forces arising from the acceleration orretardation'of the rods'S and I and acting in the longitudinal directionof these rods, also exert tilting moments on the pistons 4, 5, wherebythese pistons are turnedin the directions of the arrows I3, I 4, beingthus exposed in these places to high loads acting on the sleeves(cylinders) and to correspondingly high wear. In order to balance thesetilting moments, I arrange on the pistons additional masses l1, iii inthe same longitudinal plane as the rodsv or racks 6, I, but on thepposite side of the pistons. These additional masses follow the samerules of acceleration as the rods 6, I, so that in any position of thepistons and at any moment these additional masses l1, l8 createcountermoments for the balancing of the tilting moments of the massforces generated by the members of the coupling gear. II the additionalmasses are spaced equally from the middle axis of the pistons as therods 6, 1, the additional masses must also be equal to the masses of therods. If however the distance a between the additional mass l1 and themiddle axis should be smaller than the distance D of the rod 6 from thesame of the two masses would have to be inversely proportional to theirdistances from the middle axis.

The force created by the rotary movement of the gear wheel 8 may also bebalanced by the provision of a corresponding additional mass on theopposite side of the pistons.

I wish it to be understood that I donot desire to be limited to theexact details of-construction shown and described, for obviousmodifications will occur to a person skilled in the art.

. ype.

axis, the magnitudes 1. A tree piston engine or the opposed piston type,comprising two pistons arranged for reciprocation in oppositedirections, a coupling gearing arranged on one side of the middle axisof said pistons. and springs for creating a moment approximately equaland opposed to the tilting moment exerted by said coupling gearing onsaid pistons.

2. A free piston engine of the opposed piston comprising two pistonsarranged for reciprocation in opposite directions, a coupling gearingarranged on one side of the middle axis of said pistons, means forcreating a moment approximately equal and opposed to the tilting momentexerted by said coupling gearing on said pistons, and additional massesarranged to be set moving by said pistons only during part of the pistonstroke.

3. A free piston engine of the opposed piston type, comprising twopistons arranged for recip rocation in opposite directions, a couplinggearing arranged on one side of the middle axis of said pistons, springsfor creating a moment approximately equal and opposed to the tiltingmoment exerted by said coupling gearing on said pistons, and additionalmasses connected with said springs and arranged to be set moving by saidpistons only during part of the piston stroke.

4. A free piston engine of the opposed piston type, comprising twopistons arranged for reciprocation in opposite directions,.a couplinggearing arranged on one side of the middle axis of said pistons, andadditional masses rigidly connected with said pistons, said additionalmasses being located in positions opposed to that of said couplinggearing and adapted to create counter- Inoments approximately equallingand capable of counteracting the tilting momentsexerted by said gearingon said pistons.

v5. A'free piston engine of the opposed piston type, comprising twopistons arranged for reciprocation in opposite directions, a couplinggearing arranged on one side of the middle axis of said pistons, andadditional masses rigidly connected with said pistons, said additionalmasses being located in positions opposed to that of said couplinggearing, and adapted to create countermoments approximately equallingand capable of counteracting the tilting moments exerted by the rotaryparts of said gearing on said pistons.

HERMANN Jiimoxa.

